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Discussion Starter · #1 ·
A couple of weeks ago, after a software upload during routine 15,000-mile service on a 2018 V90 T6 AWD, the car was returned to me with the automatic brake-hold system engaged. (The one activated by the switch just aft of the parking brake on the center pedestal, with the "A" in a circle on it.) I had never activated that feature before, but I left it engaged. Seemed vaguely convenient to have the car hold position at a stop without a foot on the brake.

Now, about 1,000 miles later, I am suddenly getting strong warped-rotor pulsations upon braking. Knowing that rotors are rarely actually warped but feel that way because of deposits from the brake pads, I'm wondering: did I create a situation where the brake pads, being held tight against the rotors during every stop, left deposits on the rotors to make them feel warped?
 

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I very much doubt it. "Warped" rotors seem to usually be in the front, which is not used by Autohold. I would turn off Autohold though to get more life out of your pads, especially if you do a lot of stop and go driving.
 

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I doubt as well, the only scenario I can think is that your rear brakes were super hot and you immediately stood still for a while. That would require the brake-hold to be activated and enough time for rotors to cool off a lot (brake pad surface would cool off at a different rate than the rest of the rotor). However, that sounds very unlikely with normal city driving. I think it is just a coincidence.
 

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Discussion Starter · #4 ·
Thanks to you both. If I did have to guess, I would say that it's the front rotors that are causing the pulsations. (My wife was driving yesterday and I was riding when it first occurred, so I don't yet know if it can be felt through the wheel.)

A follow-on question: can I drive the rotors smooth again, or do they inevitably need to be turned down or replaced? And yes, I'm certainly going to turn off autohold. Pad life has been good so far. 9mm front and 10mm rear at the 15,000-mile servicing.
 

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They will likely need to be either resurfaced or replaced. Sometimes replacement can be covered under warranty.
 

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Had same issue on 2017 s60 and my 2018 s90 dealer replaced under warranty.
 

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I have not heard of the brake-hold contributing to rotor issues. I get what you're saying about the common "glazed" rotors often causing a warped rotor sensation, but I know from experience that the OEM rotors used on these cars are junk. We barely managed 7K miles on our '18 CC before beyond acceptable warping (worse on the rears) required replacement under warranty. Our '18 RD has managed to make it to 11K mi without this issue, but I'm beginning to feel something "off" or "rough" when braking. Your dealer should be able to test for excessive warping; most probably it's the rears.
 

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Both of our Volvos required new rotors after 6k and 3K miles respectively. We've never encountered rotor issues at these miles with any of our previous Volvos. I believe Volvo changed the composition of the rotors recently. More owners seem to be having front rotor issues.
 

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On my first service (10k miles) I had the dealer measure run-out on my rotors as I felt they were warped upon braking. And they were out of tolerence and had them replaced under warranty. This was something I read in another post when they brought their car in for the 10 k service. Had they're rotors replaced under warranty as well. Unfortunately I believe the warped rotors is common for some.
 

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On my first service (10k miles) I had the dealer measure run-out on my rotors as I felt they were warped upon braking. And they were out of tolerence and had them replaced under warranty. This was something I read in another post when they brought their car in for the 10 k service. Had they're rotors replaced under warranty as well. Unfortunately I believe the warped rotors is common for some.
That might have been me. My front brakes started shuddering more and more on braking prior to my 10k. They measured them as out of tolerance and replaced them without even asking. They said it's a common problem and if it happens again, they'll replace them again.
 

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They will likely need to be either resurfaced or replaced. Sometimes replacement can be covered under warranty.
Tech, Does Volvo allow you to resurface rotors? I always thought that was no Bueno. Maybe I'm getting confused on terminology.
 

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They will likely need to be either resurfaced or replaced. Sometimes replacement can be covered under warranty.
Tech, Does Volvo allow you to resurface rotors? I always thought that was no Bueno. Maybe I'm getting confused on terminology.
I'll check to see if there is an op code for warranty reimbursement. Most, if not all, dealers do not resurface because it isn't cost effective. But one time someone on here claimed their dealer does. I asked which dealer and never got an answer.

Edit: there is no warranty op code so I don't see any dealer resurfacing rotors. We replace them.
 
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